Sherman, Texas, you're almost a next door neighbor, I live on the river North of Honey Grove.
There has been discussion and a little controversy on this Forum regarding the Topsider.
If you have your oil changed at the dealer, this is the method they use. If you change oil often, you can probably get by with this.
The main reason you change the oil to begin with is that it is the only method you have for cleaning the inside of the engine. If you leave a little dirty oil in the engine, this is equivalent to driving more miles between changes.
If you hang around Mshop much you'll find that I'm an absolute maniac regarding oil changes. I drain oil usually on Friday night after driving home from Richardson. The engine is as warm as it will get. I pull the plug and let it drain overnight. Draining the oil hot gets out more contaminants because they are churned up and suspended in the oil. Draining it overnight allows the sludge to come out. The last drops that come out are the dirtiest.
I believe that my method is as thorough of a crankcase cleaning as you can get. If I were to go to the topsider method, I would change my oil more frequently to make up for leaving a small amount of sludge in the crankcase. I believe that if you were to change your interval to about 2/3 of what you would use if doing a thorough oil and filter change, you could get by with the topsider just fine.
Beware of extended oil change intervals. A pro tech on this Forum indicated that they were seeing sludge in some engines that were seeing oil changes whenever the FSS system indicated. I would change oil more frequently if this is a car that you plan to keep for some time.
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in